Field of the Invention
This invention relates to an emergency safety device for preventing a webbing from beginning to move toward an occupant-releasing position and hence for restraining an occupant in safe even if the door should open in the event of an emergency such as collision in an automatic seat belt system of the type that the webbing, which has been at an occupant-restraining position, is caused to move to the occupant-releasing position upon opening of the associated door.
The following problems have been pointed out with respect to automatic seat belt systems of the type that upon opening of an associated door, electrical drive means begins to operate so as to bring a webbing, which has been at an occupant-restraining position, toward an occupant-releasing position. An automatic seat belt system is generally convenient as an occupant is released automatically upon opening of the door. It is however not always so. When the door opens and the webbing begins to move toward the occupant-releasing position due to application of an impact to the vehicle body or tumbling of the vehicle body as a result of a collision or the like, there is a potential danger that the occupant may be released from the restraint and may no longer be protected in safe although the occupant is supposed to be restrained without failure in such an emergency.
In order to avoid such dangers, it may be contemplated to prevent the electrical drive means from beginning to operate even if the door should open in such an emergency. If one attempts to achieve this electrically as the drive means is electrical, a control circuit and wiring are required for the above purpose. This is certainly undesirable in both structure and price. Another method may also be contemplated to hold a runner or the like, which serves to move a webbing, without preventing an electrical drive means from beginning to operate. This approach is however troublesome because an undue load is applied to a motor or the like in the electrical drive means.